Related Clues:
- Long past the shelf date
- Immobile excavator losing motorway time
- Still fashionable: the Queen, top for tailoring
- Unable to react, chemically
- Past its "sell by" date, perhaps
- Far from avant-garde
- Just sitting there, as a gas
- Like krypton and some other gases
- Like yesterday's donuts
- Powerless to act, as a gas
- No longer fresh, as bread
- Nonreactive, as helium
- Like krypton or radon
- Like gas that can't pass?
- Like xenon or radon